Conventionally, techniques have been proposed which reduce the power consumption of a processing device (for example, a microprocessor) capable of performing one or more processes. For example, there are the following techniques: a dynamic voltage frequency scaling (DVFS) technique that reduces a power supply voltage or a frequency to reduce the power consumption; and a power gating technique that supplies power only to a portion requiring power.
As an example of the power gating technique, there is a technique that divides a processor into a plurality of clock domains and determines whether to supply power to each clock domain. In addition, there is a fine grain power gating technique that determines whether to supply power to each computing unit in a processor.
As another method of reducing the power consumption of a microprocessor, there is a technique that temporarily stops the entire processor to be shifted to a power saving state (sleep state).